共轭发震构造间相互作用的有限元分析

THE FINITE ELEMENT ANALYSIS OF THE INTERACTION BETWEEN CONJUGATE SEISMOGENIC STRUCTURES

摘要:

本文根据震源组合模式,利用有限元方法模拟计算,研究了共轭发震构造间的相互作用,结果如下:(1)当共轭断层的内角为压区且断层交汇区存在一定尺度的调整单元时,只有一条断层发震,另一条断层并不发震。(2)当共轭断层的内角为拉区且断层交汇区无调整单元或调整单元足够小时,由于两条共轭断层联通而发生一次大地震。(3)当共轭断层的交汇区的内角为拉区且断层交汇区有适当尺度的调整单元时,所发生的地震一般为双主震型,即两条断层均发震。其交汇区调整单元愈小,二次主震的间隔时间愈短。此外,本文还计算和讨论了调整单元尺度与初始破裂区位置的关系。

Abstract:

On the basis of the combination model of source, the interaction between conjugate seismogenic structures is calculated and modeled by using the finite element method. It gives the results as follows:
1. The single main shock type. One fault, moves and the other fault does not move, so the single main shock type is formed when the internal angle region of conjugate faults is located in compressive stress region and there exists the adjustment unit of adequate size in the intersection region of conjugate faults.
2. The conjugate single main shock type. Two conjugate faults join together and a great earth quake occurres when the internal angle region of conjugate faults is located in tensile stress region and there is not the adjustment unit or the adjustment unit is little enough.
3. The double main shock type. The double main shock type is usually formed when the inter nal angle region of conjugate faults is located.in tensile stress region and there exists the adjustment unit of adequate size in the intersection region of conjugate faults,the smaller the adjustment unit in the intersection region of conjugate faults is,the shorter the time interval between two major shocks is.
Furthermore, this paper also calculates and discusses the relation between the adjustment unit size and the location of initial fracture region in conjugate faults.